What is Methionine

Chemical Name: (2S)-2-amino-4-(methylsulphanyl)butanoic acid

Molecular Weight: 149.2

Structrual Formula:

Nitrogen Content: 9.39%

Methionine (13)

  • L-methionine is a protein amino acid. It is classified as an essential amino acid for humans and therefore must be supplied in the diet
  • One of the sulfur containing amino acids
  • Helps to initiate translation of messager RNA by being the first amino acid incorporated into N-terminal position of all proteins
  • The precursor of the amino acids taurine, cystine, cysteine
  • Belongs to group of compound called lipotropics

What is lipotropics? (122)

  • Enhance liver function
  • Increase the flow of fats and bile from the liver and gallbladder
  • By definition, a lipotropic substance decreases the deposit , or speedsup the removal of fats (lipo=fat, tropric=stimulate) within liver

Methionine and Overweight Problems (38, 39, 40, 41, 42)

Methionine and Cataract

Methionine and cholesterol (123)

  • Methionine, as a lipotropic agent, can lowers blood cholesterol
  • Methionine acts as liptropic agent, increase the production of lecithin in liver
  • The increase production of lecithin, in turn, increase the synthesis of lecithin-cholesterol acyltransferase (LCAT). (central emzyme in extracellular metabolism of plasma lipoproteins)
  • Among other substances, LCAT esterifies the free cholesterol transported in plasma lipoproteins
  • Methionine, hence, can help stabilizes cholesterol, thus lessening cholesterol desposits in blood vessels and decreasing the chance of some gallstone formation

Methionine and Brain (124)

  • Methionine is well absorbed in brain
  • Methionine is further converted into S-adenosylmethionine(SAM) by ATP (A molecules that the body continually produces to fuel numerous vital body function)
  • SAM is a very essential methyl donator
  • The SAM molecules then donates a methyl group to body tissues and organs, providing a critical link in methylation (a chemical reaction that occurs billions of times a second throughout the body )
  • In giving up a part of itself , SAM promotes cell growth and repair
  • SAM also contributes to the formation of key compounds in brain, including the neurotransmitter dopamine and the mood-enhancer serotonin

Methionine and arthristis-related pain / inflammation (125, 126)

  • After the conversion of methionine to SAM. Studies in the thousands if osteoarthritis suffers have demonstrated that SAM can be as effective at increasing joint mobility and reducing swelling and pain as such NSAIDS( nonsteroidal anti-inflammatories) as ibuprofen and aspirin
  • Although it is not exactly clear how SAM works for arthritis, very preliminary by intriguing animal studies actually point to a role in repairing cartilage and lubricating joints, properties that may well extend to humans. Clearly more research is needed.

Methionine and Parkinson’s Disease (128)

Methionine and Cataract (138)

Methionine and Muscle Protein Recovery (139)

Methionine and Menopausal Problems (129,130)

Methionine and Frigidity in Woman/Premature Ejaculation in Man (140)

Other benefits of Methionine (1)

  • Methionine is a precursor of cysteine and taurine
  • Taurine and with cholesterol, preventing gallstones
  • Cysteine is a precursor of glutathione
  • Methionine thus protects glutathione (glutathione is a key neutralizer of toxins in liver)
  • Helps to prevent glutathione depletion if the body is overload with toxins
  • Methionine works with choline to detoxify amines, which are the byproducts of protein metabolism
  • Methionine acts as a catalyst for choline and inositol, opening up their functions

Methionine and Food

  • Methionine can be found in meat, fish, beans, garlic, lentils, onions, yogurt and seeds.

Dosage of Methionine

  • Doses of L-methionine of up to 250mg daliy are generally well tolerated
  • Average-size adults (60kg) require approximately 800-1000mg of methionine per day

Adverse effect of Methionine (61)

  • Higher doses may cause nausea, vomitting and headache
  • Healthy adults taking 8 grams of L-methionine daily for four days were found to have reduced serum folate level and leucocytosis
  • Healthy adults taking 13.9 grams of L-methionine daily for 5 days were found to have changes in serum pH and potassium and increased urinary calcium excretion
  • Excessive methionine intake, together with inadequate intake of folic acid, vitamin B6 and Vitamin B12, can increase the conversion of methionine to homocysteine — a substance linked to heart diseases and stroke


  • 13) Balch, James, MD, and Phyllis Balch, CNC, Prescription for Nutritional Healing, Avery Pub., 1997.
  • 122) Cornatzer We. Lipotropic agents and lipid transport. Am J Clin Nutr. 1960 May-Jun;8:306-9
  • 123) Bagchi K. Ray R. Datta T. The influence of dietary protein and Methionine on serum cholesterol level. Am J Clin Nutr. 1963 Oct;13:232-7
  • 124) Saletu B, Anderer P, Linzmayer L, Semlitsch HV, Lindeck-Pozza E, Assandri A, di Padova C, Saletu-Zyhlarz GM. Pharmacodynamic studies on the central mode of action of S-adenosyl-L-methionine (SAMe) infusions in elderly subjects, utilizing EEG mapping and psychometry. J Neural Transm. 2002 Dec;109(12):1505-26.
  • 125) Sasaki M, Kunimatsu M, Ohkubo I. Role of calpains and kininogens in inflammation. Acta Biol Hung. 1991;42(1-3):231-42.
  • 126) Jankovic BD. Enkephalins and immune inflammatory reactions. Acta Neurol (Napoli). 1991 Oct;13(5):433-41.
  • 61) Garlick, Peter. The Nature of Human Hazards Associated with Excessive Intake of Amino Acids. J. Nutr. 2004 134: 1633-1639.
  • 128) Smythies, J. Treatment of Parkinson’s Disease with Methionine, Southern Medical Journal, 77 (12): 1577.
  • 129) Editorial in the British Medical Journal, 1: 242-3.
  • 130) Journal of Clinical Investigation, 72 (6): 1971-6.
  • 38) Heboticky, N. Effects of L-Tryptophan on short term food intake, Nutritional Research, 5(6):595-607
  • 39) Heraif, E. et al. International Journal of Eating Disorders, 4(3):281-92
  • 40) Butler R. et al. American Journal of Clinical Nutrition, 34,(10)2045
  • 41) Wurtman, R. Behavioural effects of nutrients, The Lancet, p1145
  • 42) Chaitow, L. Amino acids in therapy, Thorsons and Slimming and Health Workbook, Thorsons
  • 138) Cole, H. Enzyme activity may hold key to cataract activity, Journal of the American Medical Association 254(8): 1008
  • 139) Borsheim, Elisabet, et al. Branched-Chain Amino Acids activate key enzymes in protein synthesis after physical exercise. American Society for Nutrition J. Nutr. 136:269S-273S
  • 140) Pfeiffer, C. Mental and Elemental Nutrients, Keates Publishers, New Canaan